SUNDAY, March 18, 2018 (HealthDay News) -- Frolicking in the sea may torpedo your health, new research suggests.

It found a twofold increased risk for general ear problems, a 77 percent increased risk for earaches and a 29 percent increased risk for diarrhea and other gastrointestinal illnesses among people who swam in the sea.

The findings came from an analysis of 19 studies, involving more than 120,000 people, from the United States, the United Kingdom, Australia, New Zealand, Denmark and Norway. The results were published recently in the International Journal of Epidemiology.

"In high-income countries like the U.K., there is a perception that there is little risk to health of spending time in the sea," researcher Anne Leonard, from the University of Exeter Medical School in England, said in a news release from the school. "However, our paper shows that spending time in the sea does increase the probability of developing illnesses, such as ear ailments anad problems involving the digestive system, such as stomach ache and diarrhea.

"We think that this indicates that pollution is still an issue affecting swimmers in some of the world's richest countries," Leonard added.

Despite major improvements in water quality, seawater is still polluted from sources such as industrial waste, sewage and run-off from farmland, the researchers noted.

"We don't want to deter people from going into the sea, which has many health benefits -- such as improving physical fitness, well-being and connecting with nature," fellow researcher Will Gaze, also from the Exeter medical school, said in the news release. "However, it is important that people are aware of the risks so they can make informed decisions.

"Although most people will recover from infections with no medical treatment, they can prove more serious for vulnerable people, such as the very old or very young, or those with pre-existing health conditions," he noted.

"We have come a long way in terms of cleaning up our waters, but our evidence shows there is still work to be done," Gaze said. "We hope this research will contribute to further efforts to clean up our coastal waters."